CENTRE FOR ENVIRONMENT, FISHERIES AND
AQUACULTURE SCIENCE
SCIENCE SERIES DATA REPORT
Number 42
Spring plankton surveys of the eastern Irish Sea in
2001, 2002 and 2003:
hydrography and the distribution of
fish eggs and larvae
N. Bunn, C.J. Fox and R.D.M. Nash
LOWESTOFT
2004
1
This report should be cited as: Spring plankton surveys of the eastern Irish Sea in 2001, 2002 and 2003:
hydrography and the distribution of fish eggs and larvae. Sci. Ser., Data Rep., CEFAS Lowestoft, 42: 214pp.
The authors:
Natasha Bunn and Dr Clive Fox work in the Fisheries Biology Recruitment team at CEFAS Lowestoft. Dr Richard
Nash works for the University of Liverpool at Port Erin Marine Laboratory, Isle of Man.
Acknowledgements:
Additional participants involved in the surveys upon which this report is based were: Phil Davison (CEFAS) and
Helen Rossetti (PEML).
© Crown copyright, 2004
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2
CONTENTS
Page
1.
Introduction ....................................................................................................................................5
2.
Survey coverage ............................................................................................................................5
3.
Sampling methods and equipment ..............................................................................................5
3.1
Shipboard plankton sampling ................................................................................................5
3.2 Preservation of samples ........................................................................................................6
3.3 Identification of fish eggs and larvae .....................................................................................6
3.4 Data analysis and data storage .............................................................................................6
4.
Results ...........................................................................................................................................8
4.1
The physical environment ......................................................................................................8
4.2 The ichthyoplankton ...............................................................................................................9
4.2.1 The distributions of total eggs and total larvae ............................................................... 9
4.2.2 Clupea harengus (Herring) ........................................................................................9
4.2.3 Sprattus sprattus (Sprat) ......................................................................................... 10
4.2.4 Gadus morhua (Cod) ............................................................................................... 10
4.2.5 Melanogrammus aeglefinus (Haddock) ................................................................... 10
4.2.6 Merlangius merlangus (Whiting) .............................................................................. 10
4.2.7 Gadidae (Norway pout and Poor cod) ..................................................................... 10
4.2.8 Trisopterus luscus (Bib / Pout) ................................................................................. 10
4.2.9 Pollachius pollachius (Pollack) ................................................................................ 11
4.2.10 Gadidae (Rocklings) ................................................................................................ 11
4.2.11 Molva molva (Ling) .................................................................................................. 11
4.2.12 Triglidae (Gurnards) ................................................................................................. 11
4.2.13 Cottidae (Bullheads and Sculpins) .......................................................................... 11
4.2.14 Agonus cataphractus (Pogge) ................................................................................. 11
4.2.15 Liparis spp. (Sea-snails) .......................................................................................... 11
4.2.16 Chirolophis ascanii (Yarrell’s blenny) ....................................................................... 12
4.2.17 Pholis gunnellus (Butterfish) .................................................................................... 12
4.2.18 Ammodytidae (Sandeels) ........................................................................................ 12
4.2.19 Callionymidae (Dragonets) ...................................................................................... 12
4.2.20 Gobiidae (Gobies) ................................................................................................... 12
4.2.21 Phrynorhombus norvegicus (Norwegian top-knot) .................................................. 12
4.2.22 Zeugopterus punctatus (Topknot) ............................................................................ 12
4.2.23 Pleuronectes platessa (Plaice) ................................................................................ 13
4.2.24 Platichthys flesus (Flounder) ................................................................................... 13
4.2.25 Limanda limanda (Dab) ........................................................................................... 13
4.2.26 Microstomus kitt (Lemon sole)................................................................................. 13
4.2.27 Glyptocephalus cynoglossus (Witch) ...................................................................... 13
4.2.28 Solea solea (Sole) ................................................................................................... 13
4.2.29 Buglossidium luteum (Solenette) ............................................................................. 13
5.
References ............................................................................................................................... 212
3
Bathymetry of the Irish Sea (adapted from Dickson and Boelens, 1988)
4
1.
INTRODUCTION
3.
From January to May for the years 2001 to 2003 a
series of plankton surveys was carried out in the
eastern Irish Sea to estimate the location, magnitude
and timing of plaice spawning. The surveys were
funded by Defra project MO423. Two research
institutes took part in the surveys: The Centre for
Environment, Fisheries and Aquaculture Science
(CEFAS) and the University of Liverpool, Port Erin
Marine Laboratory (PEML). Eggs and larvae from the
target species were sorted and identified as part of the
Defra contract programme. In addition, the eggs and
larvae of all remaining fish species were analysed.
2.
SAMPLING METHODS AND
EQUIPMENT
3.1 Shipboard plankton sampling
A Gulf VII high-speed plankton sampler was used
as standard on these surveys (Nash et al., 1998). The
specification used has a 53 cm diameter unencased
body fitted with a conical nosecone of 20 cm diameter
aperture. The body of the net was made of 270 μm
mesh as standard. The cod-end consisted of a bag
constructed from an impermeable nylon material
and incorporating a window of 270 μm mesh net that
allowed the water to escape. This configuration was
designed to minimise damage to the eggs and larvae by
providing maximum protection during collection.
SURVEY COVERAGE
Table 1 summarises the timing of the surveys during
the three-year period. A grid covering the eastern
Irish Sea between 53˚ to 55˚ North and 3˚ to 4˚ 30΄
West was surveyed at approximately three-weekly
intervals. The sampling grid consisted of a total of
49 stations that aimed to include, both temporally
and spatially, the major part of the spawning of
plaice in this area (NB. For some surveys, unsuitable
weather conditions prevented completion of the full
49 stations). This design was based on the patterns of
abundance and distribution of the eggs of plaice and
cod in the Irish Sea in previous years (Nichols et al.,
1993; Armstrong et al., 1997; Fox et al., 1997; Fox et
al., 2000).
The sampler was fitted with a self-logging microconductivity-temperature-depth (CTD) sensor unit
(Falmouth Scientific, Inc., Cataumet, Massachusetts,
USA). A ‘Valeport’ (Valeport Ltd., Totnes, Devon,
U.K.) flowmeter, with a blade diameter of 12.5 cm,
was centrally mounted inside the nosecone. A similar
flowmeter was mounted externally on the frame to
provide a measure of distance travelled through the
water. Flowmeter readings (count of blade revolutions)
were provided by a Valeport self-logging readout unit.
The ratio between internal and external flowmeter
revolutions provided an index of clogging of the net,
and enabled the volume of water filtered on each
deployment to be calculated.
For a brief overview of the geography and major
hydrographic features of the study region see Nichols et
al. (1993) and OSPAR (2000).
The Gulf VII design has been extensively calibrated
over a range of speeds and simulated clogging
Table 1. Details of icthyoplankton surveys carried out in the eastern Irish Sea in
2001, 2002 and 2003
Year
Date
Vessel
Number of
stations sampled
2001
29 Jan - 1 Feb
RV Prince Madog
49
26 Feb - 2 Mar
RV Prince Madog
47
19 - 23 Mar
RV Prince Madog
46
2 -5 Apr
FV Resolute
37
23 - 26 Apr
FV Resolute
48
19 - 21 Feb
RV Prince Madog
11
13 - 16 Mar
RV Prince Madog
49
8 - 10 Apr
RV Prince Madog
49
30 Apr - 2 May
RV Prince Madog
49
13 - 17 Jan
RV Prince Madog
27
3 - 6 Feb
RV Prince Madog
30
19 - 24 Feb
RV Corystes
48
26 Feb - 1 Mar
RV Corystes
47
17 - 19 Mar
RV Prince Madog
49
12 - 15 Apr
RV Prince Madog
49
28 - 30 Apr
RV Prince Madog
41
2002
2003
5
conditions, either in a large circulating water channel or
a towing tank (Harding and Arnold, 1971; Arnold et al.,
1990; Brander et al., 1993). From these experiments,
coefficients were obtained for the regression:
carried out using a Folsom splitter. Using this method
a fraction of the sample (for example ⅛, ¼ or ½) was
worked up as appropriate.
Ichthyoplankton from these surveys was identified
according to Russell (1976). This was supplemented
by various identification guides and keys produced
by the International Council for the Exploration of
the Sea (Saville, 1964; Macer, 1967; Nichols, 1971;
Demir, 1976; Nichols, 1976). Fish eggs were initially
split into groups on the basis of presence or absence of
oil globules. Those containing either a single or many
oil globules could usually be identified to the species
level. Eggs with no oil globules are more difficult
to separate, particularly in the early stages before
embryonic pigmentation develops, and as a result it is
not possible to identify a proportion of these. However,
egg size was recorded, and the numbers of eggs without
oil globules that were measured (i.e. not total numbers)
for each survey are shown in Figures 1 to 3. Overall,
the patterns of size frequency reveal a bi-modal
distribution in egg diameter with highest numbers
occurring at around 0.8 mm and 1.2 mm. The first
peak is likely to consist of eggs mainly from species
such as dab (Limanda limanda) and to a lesser extent
flounder (Platichthys flesus). Eggs measuring from
about 1.0 to 1.25 mm in diameter cover a larger range
of species including whiting (Merlangius merlangus),
witch (Glyptocephalus cynoglossus), Trisopterus spp.
(Norway pout, poor cod, bib) and others. Eggs of
cod (Gadus morhua) and haddock (Melanogrammus
aeglefinus) also overlap with the upper end of this
range. Fish larvae were generally easy to identify
unless they had been badly damaged during collection.
For some groups, such as the sandeels (Ammodytidae)
and the rocklings (Gadidae), individuals were not
identified to the species level.
y = a*x + b
where, y = volume filtered (litres per internal
flowmeter count),
x = ratio of internal to external flowmeter
counts,
a = -101.44
and
b = 225.52.
These data were used to calculate the volume filtered
during each sampler deployment.
The sampler was deployed in an oblique tow, at
4-5 knots, from the surface to within 2 metres of the
bottom (or as near as bottom topography would allow)
and returned to the surface. The requirement was for
an even ‘V’-shaped dive profile, filtering the same
volume of water per unit of depth. The aim was to shoot
and haul at the same rate with the sampler spending
approximately 10 seconds in each 1-metre depth band.
At shallow stations, more than one dive was necessary
to enable a sufficient volume of water to be filtered.
It was recommended that the sampler remained in the
water for a minimum period of 15 minutes.
Temperature, salinity and depth profiles were
obtained at each sampling position from the CTD
sensor mounted on the frame of the plankton sampler.
Additional salinity bottle samples were taken at regular
intervals from the near surface in order to validate the
quality of the salinity data taken from the CTD.
3.2 Preservation of samples
3.4 Data Analysis and data storage
After the sampler had been recovered the net was
gently washed down from the outside with seawater.
The end-bag was removed and the plankton washed
into a jar and fixed using buffered formaldehyde
solution (4% formaldehyde in distilled water buffered
with 2.5% sodium trihydrate (w/v), (Tucker and
Chester, 1984). The samples were transported to the
CEFAS laboratory, Lowestoft, for plankton sorting and
identification.
Plankton data were expressed as number of organisms
m-3 by dividing the numbers per sample by the volume
filtered. The plankton distributions in this report
are plotted as numbers m-2 of sea surface, obtained
by multiplying the number m-3 by the sampled depth
during deployment. Numbers m-2 of sea surface
were plotted as bubbles on the same linear scale for
a species for all surveys in any given year. Bubble
diameter is linearly related to numbers m-2 above a
non-zero baseline of 0.1 m-2 (Surfer version 8, Golden
Software Inc., Colorado, U.S.A.). Hydrographical data
was plotted as contour maps using the same software.
Values were obtained from the CTD data recorded
during each sampler deployment. The full dataset is
stored on ACCESS (Microsoft Inc.) databases held at
CEFAS.
3.3 Identification of fish eggs and
larvae
Fish eggs and larvae were picked out of the preserved
samples using low power microscopes, and, whenever
practicable, the whole sample was sorted. Subsampling, however, was at times necessary and this was
6
40
250
29 Jan - 1 Feb
26 Feb - 2 Mar
200
Total numbers
30
150
20
100
10
50
0
0
0.6
0.8
1.0
1.2
1.4
Egg diameter (mm)
1.6
0.6
120
0.8
1.0
1.2
1.4
Egg diameter (mm)
120
2 - 5 Apr
19 - 23 Mar
Total numbers
1.6
100
100
80
80
60
60
40
40
20
20
0
0
0.6
0.8
1.0
1.2
1.4
1.6
0.6
0.8
Egg diameter (mm)
1.0
1.2
1.4
1.6
Egg diameter (mm)
80
23 - 26 Apr
Total numbers
60
40
20
0
0.6
0.8
1.0
1.2
1.4
1.6
Egg diameter (mm)
Figure 1.
Size-frequencies of measured unidentified eggs by cruise in 2001
250
30
25
Total numbers
13 - 16 Mar
19 - 21 Feb
200
20
150
15
100
10
50
5
0
0
0.6
0.8
1.0
1.2
1.4
1.6
0.6
0.8
1.2
1.4
1.6
100
140
30 Apr - 2 May
8 - 10 Apr
120
Total numbers
1.0
Egg diameter (mm)
Egg diameter (mm)
80
100
80
60
60
40
40
20
20
0
0
0.6
0.8
1.0
1.2
1.4
1.6
0.6
Egg diameter (mm)
Figure 2.
0.8
1.0
1.2
Egg diameter (mm)
Size-frequencies of measured unidentified eggs by cruise in 2002
7
1.4
1.6
Total numbers
10
100
13 - 17 Jan
8
80
6
60
4
40
2
20
0
3 - 6 Feb
0
0.6
0.8
1.0
1.2
1.4
1.6
0.6
0.8
1.0
1.2
1.4
800
800
Total numbers
19 - 24 Feb
26 Feb - 1 Mar
600
600
400
400
200
200
0
0
0.6
0.8
1.0
1.2
1.4
Egg diameter (mm)
1.6
0.6
0.8
1.0
1.2
1.4
Egg diameter (mm)
1.6
140
300
17 - 19 Mar
12 - 15 Apr
120
250
Total numbers
1.6
Egg diameter (mm)
Egg diameter (mm)
100
200
80
150
60
100
40
50
0
0.6
20
0
0.8
1.0
1.2
1.4
1.6
0.6
Egg diameter (mm)
0.8
1.0
1.2
1.4
1.6
Egg diameter (mm)
140
28 - 30 Apr
Total numbers
120
100
80
60
40
20
0
0.6
0.8
1.0
1.2
1.4
1.6
Egg diameter (mm)
Figure 3.
4.
Size-frequencies of measured unidentified eggs by cruise in 2003
here. The Irish Sea is characterised by a deep water
trough (>80 m) running centrally between the Irish coast
and following a line from the southern tip of the Isle
of Man to the west of Anglesey. The trough continues
northwards through the North Channel reaching a depth
of 315 m at Beauforts Dyke. In the central area the
trough shallows rapidly to the west whilst to the east
it slopes more gently to create a relatively shallow bay
(<50 m deep) bordered by the North Wales, English and
Scottish coasts (eastern Irish Sea).
RESULTS
4.1 The physical environment
The bathymetry and oceanography of the Irish Sea
have been extensively described (Robinson, 1979;
Bowden, 1980; Proctor, 1981; Dickson and Boelens,
1988; OSPAR, 2000). However, because the physical
environment plays such an important role in determining
the biological processes, a brief account is included
8
level only (e.g. Rocklings, Trigla spp., Ammodytidae,
Gobiidae). All species and taxonomic groups are listed
in Tables 2a-d. These tables also record the maximum
density of eggs and larvae found on each survey and
their occurrence as a percentage of the stations where a
positive record was obtained. Figures 28 to 147 map the
egg and larval distributions for most of the identifiable
species by survey. A ‘+’ symbol denotes a station where
a plankton tow was carried out, but no eggs or larvae of
the species indicated were caught.
Details of the circulation and tidal movements within
the Irish Sea can be found in Ramster and Hill (1969),
Simpson and Hunter (1974), Slinn (1974), Heaps and
Jones (1977), Bowden (1980), Davies and Jones (1992),
Hill et al. (1994), OSPAR (2000), Young et al. (2001).
In most of the region, tidal mixing is sufficiently strong
to maintain a vertically homogeneous water column
throughout the year. An exception to this is the area
to the southwest of the Isle of Man where the water is
deep and the tidal flows weak. Seasonal stratification
is established in this area between April and October
leading to a density driven gyre. In the eastern Irish
Sea, haline stratification is marked in winter and
spring, especially near the main river inputs, but
thermal stratification may develop in the summer.
4.2.1 The distributions of total eggs
and total larvae (Figures 22 and 27)
In all years and surveys fish eggs were found at nearly
every position sampled. Peak numbers generally
occurred off the north Wales coast in early to midMarch. The highest number recorded during any one
survey was 8085 m-2 in March 2003. High abundances
could also be found in the waters between the Isle of
Man and the coast of Cumbria. In the later surveys fish
eggs were more evenly distributed across the region in
lower densities.
Figures 4 to 6 show the sea surface temperature
distributions from January to May for 2001-2003
in the eastern Irish Sea. For all years a similar
general pattern is evident (NB. survey coverage in
early 2002 and 2003 was comparatively poor due
to unsuitable weather conditions). In January and
February minimum temperatures (down to 5ºC in
February 2001) were recorded along the length of the
English coast. At the same time surface temperatures
gradually increased with increasing distance from the
coast. This east to west gradient in temperature was
maintained during March but at an average of 0.5-1ºC
higher. By April, surface temperatures had continued
to rise but were now relatively uniform across the
whole of the survey area. Highest temperatures of
9.5ºC were recorded at the end of April in 2002 and
2003. Patterns in bottom temperature (Figures 79) showed very similar patterns to surface values
indicating that the water column was well mixed
across the region. Overall, temperatures appeared
lower in 2001 than in the other years. Integrated
temperatures (temperature averaged over the whole
water column) are plotted in Figures 10 to 12.
Larvae were recorded in relatively low concentrations
in all years during January and February. By midMarch increased numbers were found, especially in
the areas off the north Wales coast (2002) and between
the Isle of Man and Cumbria (2001 and 2003). Peak
abundances occurred over a wide area towards the end
of April. Maximum larval density was 2387 m-2 in the
last survey of 2001.
4.2.2. Clupea harengus (Herring)
(Figures 28-30)
Herring are demersal spawners that deposit their eggs
to form a mat on the bottom substrate. Thus, no eggs
of herring were caught during these surveys. Herring
larvae are difficult to distinguish from another Clupeid,
sprat (Sprattus sprattus), but separation is made
possible by differences in the number of muscle blocks
running the length of the larvae. The Irish Sea herring
stock spawns in the autumn so most of the Clupeid
larvae caught in these spring surveys were those of S.
sprattus. However, some herring larvae were found
in small numbers across the eastern Irish Sea over the
period sampled. Highest densities (up to 31 m-2) and
widest distribution, both temporal and spatial, occurred
in the 2003 surveys. Peak abundances were recorded
in January and February in each year but a few larvae
were still present in April at discrete positions in 2003.
Herring spawn as late as November in the Irish Sea
so it is thought that the larvae identified in this survey
series were the product of late spawning from the
previous year. It is also possible that larvae from the
Celtic Sea spawning area may have drifted into the
region, but this has yet to be tested (Mike Armstrong,
CEFAS, pers. com.)
The patterns of surface salinity distribution (Figures
13-15) show a similar trend to those of temperature,
incrementing in value from sites off the English coast
towards the western Irish Sea. Minimum and maximum
values were 31 (March 2002) and 34 (most surveys).
Little difference in salinity occurred between years.
However, compared to previous surveys carried out
over the same time period in 2000 (Bunn and Fox,
2003), salinities are generally higher. Bottom and
integrated salinity patterns follow similar contours to
the surface. This implies that there was little vertical
structure in salinity (Figures 16-21).
4.2 The ichthyoplankton
Over the 3-year period surveyed, fish eggs from 19
species and larvae from 30 species were identified. A
further 4 groups of eggs and 9 groups of larvae were,
for practical reasons, identified to the family or genus
9
numbers generally occurred in all years in early to midApril. The maximum larval abundance recorded was 22
m-2 off the Cumbria coast in 2003.
4.2.3 Sprattus sprattus (Sprat)
(Figures 31-36)
Sprat eggs were identified from early February onwards
and overall were the most abundant in both number
and distribution throughout the series (Tables 2a and
c). During the March and April surveys eggs were
caught at an average of 91% of the stations sampled.
The maximum densities recorded were 826 m-2 in April
2001, 534 m-2 in March 2002 and 484 m-2 in April 2003.
Between years patches of higher abundance occurred
in two main areas: Liverpool Bay and the North Wales
coast, and between the Isle of Man and the English
coast. Sprat larvae were also widespread, especially
from late-March onwards, and followed a similar
pattern to the eggs with peak concentrations occurring
predominantly in shallower coastal waters. Highest
numbers (up to 848 m-2) were recorded in the final
survey of 2001.
4.2.5 Melanogrammus aeglefinus
(Haddock) (Figures 43-48)
Because of the problems encountered with
identification, haddock eggs were handled and
recorded in the same way as those of G. morhua. Latestage haddock eggs were caught at isolated positions
on only 4 of the 16 surveys over the 3-year period.
These were in fact single individuals and nearly all
of them were caught in a similar area near the Isle of
Man in March. Higher numbers of larvae were found
but their distribution was also restricted to small
areas. Peak densities were 3 m-2 in March 2001, 5 m-2
in April 2002 and 4.8 m-2 in late April 2003.
4.2.6 Merlangius merlangus (Whiting)
(Figures 49-51)
4.2.4 Gadus morhua (Cod)
(Figures 37-42)
The eggs of this species are not separately identified
but are included in a group of measured eggs with no
oil globules (Figures 1-3). Russell (1976) established
that whiting eggs range in diameter from 0.97 to
1.32 mm. However, recent evidence using ‘TaqMan’
molecular probes to identify egg species has shown that
the range for whiting may extend up to 1.7 mm in the
Irish Sea (Fox et al., in prep).
Cod and haddock (Melanogrammus aeglefinus)
produce eggs that are identical in appearance during
their early stages of development and also overlap
in size range. Therefore, they cannot be positively
distinguished. For this survey series, using sizes
determined by Russell (1976) early-stage eggs
measuring 1.24-1.7 mm diameter and lacking an oil
globule were classified as ‘cod-like’. These have not
been mapped separately, but measured eggs in this
range are included in Figures 1 to 3 that show the sizefrequencies of unidentifiable eggs. From these figures
it may be assumed that a proportion of these eggs were
cod, but their concentration and distribution in terms
of abundance is unknown. Recent studies of ‘cod-like’
eggs caught in the Irish Sea have applied molecular
techniques to provide a firm identification of species
(Fox et al., in prep.). Initial results have shown that cod
and haddock eggs also overlap significantly in size with
those of whiting (Merlangius merlangus) whose upper
size limit was determined by Russell (1976) to be 1.32
mm diameter. Moreover, the ‘TaqMan’ analyses used
showed that the majority of ‘cod-like’ eggs in the size
range 1.2-1.75 mm (and therefore previously assumed to
be cod or haddock) were in fact from whiting.
Whiting larvae were found to be widespread in the
eastern Irish Sea from mid-March and overall this
species was the nth most abundant in the survey series.
Highest densities occurred in mid or late April. The
maximum number recorded was 128 m-2 in 2003.
4.2.7 Gadidae (Norway Pout and Poor
Cod) (Figures 52-54)
The eggs of these two species are similar to those of
M. merlangus and others and so are not identified in
plankton samples (see Figures 1-3). Similarly the larvae
of Trisopterus minutus (Norway pout) and T. esmarkii
(poor cod) are difficult to distinguish between, and
for the purposes of plotting, positively identified
larvae have been grouped together with unidentifiable
individuals. Larvae were caught as early as February
in 2001 and 2003, but in 2002 were not identified from
samples until the first survey in April. Numbers were
generally low and patchy in distribution in 2001-02.
The greatest numbers (up to 28 m-2) were recorded
during one survey in April 2003.
Late-stage (stages IV and V) cod eggs are more
easily identifiable by the development of embryonic
pigmentation. However, these too are subject to misidentification and so the results plotted here must be
taken as an indication only of their true abundance.
Late-stage cod eggs were recorded from early February
until middle or late-April. Peak abundances occurred in
mid-March in all years. Overall numbers were lowest in
2003. In this year eggs were predominantly confined to
the northern part of the area, whereas in 2001 and 2002
they were more widespread. By the end of April in all
years egg numbers were low or absent. Cod larvae were
found at the beginning of February in 2003, but highest
4.2.8 Trisopterus luscus (Bib, Pout)
(Figures 55-57)
The eggs of this species lack an oil globule and range
in diameter from 0.9-1.23 mm. They cannot readily be
separated from those of a similar size (Figures 1-3).
10
Over the survey series bib larvae were more common in
number and distribution than those of its close relatives
Trisopterus minutus and T. esmarkii. Maximum larval
densities reached 25 m-2, 8 m-2 and 38 m-2 in 2001, 2002
and 2003 respectively.
4.2.12 Triglidae (Gurnards)
(Figures 73-75)
Neither the eggs nor larvae of this group are routinely
identified to genus or species. However, four species
occur in the Irish Sea, the most common being Eutrigla
gurnardus (grey gurnard) which spawns from January
to June. The three other species are Aspitrigla cuculus
(red gurnard) which spawns from April to August
in the eastern Irish Sea, Trigla lucerna (tub gurnard)
which spawns from May to July and the less common
Trigloporus lastoviza (streaked gurnard) which spawns
from June to August. Gurnard eggs were relatively scarce
from January to March. Maximum abundances occurred
in April, but eggs were still only found at <50% of the
positions sampled. Comparison between years showed
that higher numbers were caught over a wider area in
both 2002 and 2003 than in 2001. The larvae occurred at
such low incidences (Tables 2b and d) that they have not
been mapped. Triglidae predominantly feed on bottomdwelling animals such as crustaceans and small fish.
The larvae rarely feature strongly in plankton samples
suggesting that they have already dropped out of the water
column to feed and are situated close to the seabed.
4.2.9 Pollachius pollachius (Pollack)
(Figures 58-60)
Pollack is another species to produce eggs of a similar
size range and appearance to others that lack an oil
globule. Pollack eggs range in diameter from 1.11.22 mm and because this overlaps with Merlangius
merlangus and Trisopterus luscus they are not
separately identified (Figures 1-3). Larvae were caught
in relatively low numbers in all years. Maximum
abundance was 5 m-2 in 2003. No distinct pattern in
distribution was evident.
4.2.10 Gadidae (Rocklings)
(Figures 61-66)
Four species of rockling are found in the Irish Sea,
Gaidropsarus mediterraneus (shore rockling),
Gaidropsarus vulgaris (three-bearded rockling),
Enchelyopus cimbrius (four-bearded rockling) and
Ciliata mustela (five-bearded rockling). Rockling eggs
are small in diameter (0.5-0.99 mm) with a single oil
globule. However, they are not identified to the species
level in plankton samples. G. mediterraneus spawns
inshore in June and July and E. cimbrius spawns in
deeper water (>50 m) from May to August (Wheeler,
1978). Therefore it is unlikely that either species
features in these surveys. G. vulgaris spawns in shallow
water in January and February, and C. mustela spawns
offshore in winter and spring, so both of these species
may be present. Rockling eggs occurred in coastal
areas in January and February. By March numbers had
increased and distribution was widespread. Highest
densities (<121 m-2) were found during the last survey
in 2002. Rockling larvae were caught throughout the
eastern Irish Sea, predominantly in late-April. Peak
abundances occurred in an area southeast of the Isle
of Man and to a lesser extent offshore from the north
Wales coast in 2001 and 2002.
4.2.13 Cottidae (Bullheads and
Sculpins) (Figures 76-78)
Bullheads and sculpins are a shallow water family that
deposit benthic eggs on rocky or weedy substrate. The
younger larval stages are not easily identified to species
and have therefore been grouped together as Cottidae
for analysis. However, based on larger individuals, two
species were identified in these surveys Myoxocephalus
scorpius (Bull-rout) and Taurulus bubalis (Sea
scorpion). For presentation their numbers have been
combined with unidentified specimens, but details for
each species can be found in Tables 2b and d. Cottidae
larvae were found in small numbers at coastal sites in
February and March. In April their distribution was
more widespread and peak numbers (4-9 m-2) were
recorded on the last survey in all years.
4.2.14 Agonus cataphractus (Pogge)
(Figures 79-81)
The eggs of this species are benthic. Pogge larvae
occurred from March onwards in low concentrations.
They were distributed at mainly coastal positions and
the maximum density recorded was 3 m-2 in 2003,
although overall occurrence was lowest in this year.
4.2.11 Molva molva (Ling)
(Figures 67-72)
Ling is described as an inhabitant of deep water (300400 m) or shallower water on suitable open ocean
coasts (Wheeler, 1978). The females spawn between
March and July on grounds that are found mostly to the
north of the British Isles. Ling is therefore uncommon
in the Irish Sea. However, the eggs were caught
sporadically during this survey series at a small number
of stations (Tables 2a and b). Most occurred from lateMarch, but in 2003, one individual was identified at the
beginning of February. Maximum egg concentrations
were <4 m-2 in all years. Few larvae were found.
4.2.15 Liparis spp. (Sea-snails)
(Figures 82-84)
Sea-snails are another shallow water group with a benthic
egg. They most commonly occur close to the coast, a
pattern supported by the larval distribution in the eastern
Irish Sea, with highest concentrations being caught off
the north Wales coast. Larvae were identified from midMarch but numbers were greatest during April.
11
Channel it may spawn from April to September (Demir,
1976). The distributions of eggs and larvae from these
surveys are therefore likely to be mainly a mixture of C.
lyra and C. maculatus. The eggs were caught on every
survey throughout the 3-year study period, increasing
in number and distribution before reaching a peak
around the middle of April. Concentrations of between
180-225 m-2 were recorded for a number of stations,
particularly in an area of water stretching between the
Isle of Man and the north Wales coast. In 2002-03,
numbers were found to have declined slightly by the
end of the survey series. Dragonet larvae occurred in
a similar geographical pattern to the eggs. The highest
concentrations were recorded at the end of April; these
were 129 m-2 in 2001, 98 m-2 in 2002 and 78 m-2 in 2003.
4.2.16 Chirolophis ascanii
(Yarrell’s blenny) (Figures 85-87)
The eggs of this species are benthic. In 2001 and 2002
larvae were caught from mid-March at no more than one
station per survey. A few more individuals were found in
2003, but overall concentrations did not exceed 1.5 m-2.
4.2.17 Pholis gunnellus (Butterfish)
(Figures 88-90)
Butterfish are common on rocky substrates,
particularly inshore, and produce benthic eggs. They
may also be found offshore on sand or mud where they
deposit their eggs in the shells of bivalve molluscs
(Wheeler, 1978). The spawning period in the Irish Sea
is from January to March (Qasim, 1956). In the eastern
Irish Sea in 2001-02, butterfish larvae were relatively
abundant from mid-March onwards. The maximum
concentration recorded was 18 m-2. In 2003, however,
comparatively few larvae were caught until the final
survey at the end of April.
4.2.20 Gobiidae (Gobies)
(Figures 100-102)
Gobiidae are a large group of fish common in inshore
waters and producing benthic eggs. Up to 11 species
are found in the Irish Sea. Their larvae are not
well described, and although easy to identify as a
group because of their prominent swim bladder and
characteristic pigmentation, they are not routinely
identified to species level. Larvae were found in low
numbers at predominantly coastal sites until the last
survey in each year. By the end of April distribution
was widespread, particularly in 2002 and 2003.
Abundances were in the main part less than 12 m-2,
however, a much higher density of 96 m-2 was recorded
in May 2002 north of Liverpool Bay. Interestingly, a
similar phenomenon was observed at the same site in a
previous study in 2000 (Bunn and Fox, 2004).
4.2.18 Ammodytidae (Sandeels)
(Figures 91-93)
Four out of the five species of Ammodytidae occur
in the Irish Sea although one of these, Ammodytes
tobianus, spawns in the autumn and is therefore
unlikely to feature as larvae in spring surveys. Of
the other three species, Ammodytes marinus (Raitt’s
sandeel) is common offshore and spawns from January
to March, Gymnammodytes semisquamatus (smooth
sandeel) spawns from April to July and Hyperoplus
lanceolatus (greater sandeel), which is very common
and widely distributed, spawns in April and May. The
eggs of the whole of this group are benthic and are
therefore not caught in the plankton. For these surveys,
the larvae have not been identified to species, although
this is possible using descriptions by Macer (1967) and
Russell (1976). In all years, larvae were uncommon
until the surveys in mid-March when numbers
increased significantly over the whole region. Peak
abundances (up to 239 m-2 in 2001) occurred close to
the Scottish and north Welsh coasts.
4.2.21 Phrynorhombus norvegicus
(Norwegian top-knot)
(Figures 103-108)
Norwegian topknot spawn in late spring and summer,
so the peak of spawning is likely to occur later than
the period covered by these surveys. Hence, eggs of
this species were found mainly in April, but were first
identified at the start of February in 2003. Distribution
was generally greater in 2002-03 than in 2001.
Norwegian topknot larvae were caught rarely. Highest
concentrations (up to 13 m-2) were recorded in lateApril 2003.
4.2.19 Callionymidae (Dragonets)
(Figures 94-99)
The eggs of Callionymidae have a sculpted case and
are therefore very distinct. Eggs and larvae of the two
species commonly occurring in this area have not been
separately identified from these surveys. Callionymus
lyra (common dragonet) is reported to spawn from late
January through to August (Russell, 1976) in water <50
m. Callionymus maculatus (spotted dragonet) spawns
from April to August and shows a preference for deeper
water. There is no information on the spawning in the
Irish Sea of a third species, Callionymus reticulatus
(reticulated dragonet). This species is uncommon
but reputed to frequent shallow water. In the English
4.2.22 Zeugopterus punctatus
(Topknot) (Figures 109-114)
Spawning of this species is reported to occur around
the Irish Sea in April at predominantly coastal sites
(Bunn and Fox, 2004). The distributions presented
for the eastern Irish Sea were consistent with this.
The eggs of this species were less abundant than the
Norwegian topknot and reached a maximum of 8 m-2.
Larval concentrations were relatively low and patchy,
with little difference evident between years.
12
4.2.23 Pleuronectes platessa (Plaice)
(Figures 115-120)
4.2.26 Microstomus kitt (Lemon sole)
(Figures 127-132)
Plaice spawn from late-December to May and therefore
egg production was well underway by the start of each
year’s sampling period. Three main areas of spawning
are reported for the Irish Sea; off the Irish coast,
between the Isle of Man and the Cumbria coast, and
off the North Wales coast (Nichols et al., 1993; Fox et
al., 1997; Fox et al., 2000). The data presented here
supports this pattern for the eastern Irish Sea and it is
particularly evident in 2003 when extensive spawning
was observed from mid-February to mid-March. Peak
concentrations were similar between years (between
185 and 212 m-2). However, highest abundances
occurred over a wider area in 2003 compared with the
other two years when numbers were generally moderate
(<60 m-2). By the last survey of each year, plaice eggs
had decreased significantly and few were caught
except in the waters near Anglesey. Plaice larvae were
recorded on every survey but were most abundant
numerically in March and April. Larval distributions
were more widespread in 2001-02 than 2003 (Tables 2b
and d) even though the egg data might have predicted
otherwise. Maximum larval abundance was 71 m-2 in
May 2002.
Lemon sole is reported to spawn in spring and summer
in depths of about 100 m, i.e. deeper than found in
the eastern Irish Sea (Wheeler, 1978). Eggs of this
species can only be positively identified at a late stage
of development when characteristic pigmentation of
the embryo is visible. Very few late stage eggs were
recorded on these surveys and maximum concentration
did not exceed 1 m-2. The larvae were also relatively
low in concentration and occurred irregularly in March
and April.
4.2.27 Glyptocephalus cynoglossus
(Witch) (Figures 133-135)
Like those of Microstomus kitt, witch eggs can only
be identified in the late embryonic stages. No latestage witch eggs were recorded in the eastern Irish
Sea in this study. However, low numbers occurred in
the western Irish Sea in 2000 (Bunn and Fox, 2004),
so it may be assumed that the majority of spawning
occurs here in the deeper water that is preferred by this
species. Larvae were found in relatively low densities.
Distributions peaked in the latter half of April in all
years and maximum concentrations were comparable
between years.
4.2.24 Platichthys flesus (Flounder)
(Figures 121-123)
4.2.28 Solea solea (Sole)
(Figures 136-141)
The eggs of this species have no oil globule and range
in diameter from 0.8-1.13 mm (Figures 1-3). They are
indistinguishable from eggs of a similar size such as
Limanda limanda (dab) and Trisopterus luscus (bib).
The adults inhabit coastal, estuarine and brackish
waters but spawning is known to occur offshore. In
this survey series, flounder larvae were common
throughout the region, but were most abundant in the
waters between the Isle of Man and the north Wales
coast. Numbers and distribution steadily increased
during March and into April and concentrations were
on average less than 100 m-2. However, at one site close
to the Isle of Man in April 2001, abundance reached a
high of 502 m-2.
Sole live at relatively shallow depths (<100 m) and
spawn in spring and early summer in coastal waters.
In the Irish Sea as a whole, the majority of spawning
occurs in the eastern part, with very little being
observed west of 04º 30΄W (Fox et al., 1997; Bunn and
Fox, 2004). In 2001-03 peak spawning was observed
off the north Wales coast in April. Sole larvae were
uncommon from February to the end of April. Highest
abundances (up to 23 m-2) were also found in the waters
close to the north Welsh coast.
4.2.29 Buglossidium luteum (Solenette)
(Figures 142-147)
4.2.25 Limanda limanda (Dab)
(Figures 124-126)
Solenettes are another shallow-water species. In
the eastern Irish Sea in 2001-03 they were found to
spawn slightly later than sole and were more common
in the inshore waters along the English coast. Peak
concentrations were 26, 172 and 193 m-2 for the three
respective years. Few larvae were caught in 2001 but
this was consistent with what might be expected from
the numbers of eggs observed and the timing of the
last survey. However, larval densities were higher in
the two following years and distribution was mainly
concentrated off the north Wales coast.
Dab are another species that produce small eggs with
no oil globule, making them indistinguishable from
similar sized eggs produced by other fish (Figures 1
to 3). Dab larvae were recorded from January (2003)
but were not widespread until mid to late February.
Although the larvae were found throughout the eastern
Irish Sea, highest concentrations occurred off the north
Wales coast and in a band spreading northwards from
this area. Average numbers (max. 1222 m-2) were much
higher in 2001 and 2003 than in 2002. Overall dab
were the most abundant larvae found during the survey
series (Tables 2b and d).
13
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
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23 - 26 April
55°
54°
53°
52°
6°
Figure 4.
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
Surface temperatures (°C) in 2001
14
6°
5°
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
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Figure 5.
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
Surface temperatures (°C) in 2002
15
6°
5°
4°
3°
13 - 17 January
3 - 6 February
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55°
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53°
53°
52°
6°
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54°
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6°
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17 - 19 March
55°
54°
54°
53°
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Figure 6.
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
52°
5°
26 February - 1 March
19 - 24 February
52°
6°
52°
6°
5°
4°
3°
6°
Surface temperatures (°C) in 2003
16
5°
28 - 30 April
55°
54°
53°
52°
Figure 6.
6°
5°
4°
3°
continued
17
29 January - 1 February
26 February - 2 March
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55°
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52°
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5°
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52°
23 - 26 April
55°
54°
53°
52°
6°
Figure 7.
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
Bottom temperatures (°C) in 2001
18
6°
5°
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
Figure 8.
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
Bottom temperatures (°C) in 2002
19
6°
5°
4°
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
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3°
55°
54°
54°
53°
53°
6°
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3°
6°
17 - 19 March
55°
54°
54°
53°
53°
Figure 9.
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
3°
6°
Bottom temperatures (°C) in 2003
20
5°
28 - 30 April
55°
54°
53°
52°
Figure 9.
6°
5°
4°
3°
continued
21
29 January - 1 February
26 February - 2 March
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55°
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23 - 26 April
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54°
53°
52°
6°
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3°
4°
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2 - 5 April
19 - 23 March
55°
52°
5°
Figure 10. Integrated temperatures (°C) in 2001
22
6°
5°
19 - 21 February
13 - 16 March
55°
55°
54°
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53°
52°
6°
5°
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6°
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3°
30 April - 2 May
8 - 10 April
55°
52°
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4°
52°
3°
Figure 11. Integrated temperatures (°C) in 2002
23
6°
5°
4°
3°
13 - 17 January
3 - 6 February
55°
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17 - 19 March
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12 - 15 April
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53°
52°
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26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 12. Integrated temperatures (°C) in 2003
24
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Figure 12. continued
25
29 January - 1 February
26 February - 2 March
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23 - 26 April
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2 - 5 April
19 - 23 March
55°
52°
5°
Figure 13. Surface salinities (psu) in 2001
26
6°
5°
19 - 21 February
13 - 16 March
55°
55°
54°
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53°
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6°
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30 April - 2 May
8 - 10 April
55°
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5°
4°
52°
3°
Figure 14. Surface salinities (psu) in 2002
27
6°
5°
4°
3°
13 - 17 January
3 - 6 February
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55°
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17 - 19 March
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12 - 15 April
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26 February - 1 March
19 - 24 February
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3°
6°
Figure 15. Surface salinities (psu) in 2003
28
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
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3°
Figure 15. continued
29
29 January - 1 February
26 February - 2 March
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23 - 26 April
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2 - 5 April
19 - 23 March
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Figure 16. Bottom salinities (psu) in 2001
30
6°
5°
19 - 21 February
13 - 16 March
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30 April - 2 May
8 - 10 April
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Figure 17. Bottom salinities (psu) in 2002
31
6°
5°
4°
3°
13 - 17 January
3 - 6 February
55°
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17 - 19 March
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12 - 15 April
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5°
26 February - 1 March
19 - 24 February
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4°
6°
3°
Figure 18. Bottom salinities (psu) in 2003
32
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Figure 18. continued
33
29 January - 1 February
26 February - 2 March
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23 - 26 April
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6°
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2 - 5 April
19 - 23 March
55°
52°
5°
Figure 19. Integrated salinities (psu) in 2001
34
6°
5°
19 - 21 February
13 - 16 March
55°
55°
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6°
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30 April - 2 May
8 - 10 April
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5°
4°
52°
3°
Figure 20. Integrated salinities (psu) in 2002
35
6°
5°
4°
3°
13 - 17 January
3 - 6 February
55°
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17 - 19 March
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12 - 15 April
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5°
26 February - 1 March
19 - 24 February
55°
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6°
52°
6°
5°
4°
6°
3°
Figure 21. Integrated salinities (psu) in 2003
36
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
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3°
Figure 21. continued
37
29 January - 1 February
26 February - 2 March
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53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1389.3
2778.4
53°
4209.7
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 22. Total egg concentrations (nos.m-2) in 2001
38
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
976.7
1953.3
2959.5
Symbols on linear scale
Figure 23. Total egg concentrations (nos.m-2) in 2002
39
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 24. Total egg concentrations (nos.m-2) in 2003
40
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
2668.0
5335.9
8084.7
Symbols on linear scale
Figure 24. continued
41
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
787.7
1575.3
53°
2386.7
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 25. Total larval concentrations (nos.m-2) in 2001
42
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
215.3
430.5
652.3
Symbols on linear scale
Figure 26. Total larval concentrations (nos.m-2) in 2002
43
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 27. Total larval concentrations (nos.m-2) in 2003
44
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
350.1
700.1
1060.7
Symbols on linear scale
Figure 27. continued
45
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
3.0
6.0
53°
9.0
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 28. Concentration of herring (Clupea harengus) larvae (nos.m-2) in 2001
46
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
0.6
1.1
1.6
Symbols on linear scale
Figure 29. Concentration of herring (Clupea harengus) larvae (nos.m-2) in 2002
47
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 30. Concentration of herring (Clupea harengus) larvae (nos.m-2) in 2003
48
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
10.3
20.5
31.0
Symbols on linear scale
Figure 30. continued
49
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
272.6
545.0
53°
825.7
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 31. Concentration of sprat (Sprattus sprattus) eggs (nos.m-2) in 2001
50
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
176.4
352.7
534.4
Symbols on linear scale
Figure 32. Concentration of sprat (Sprattus sprattus) eggs (nos.m-2) in 2002
51
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 33. Concentration of sprat (Sprattus sprattus) eggs (nos.m-2) in 2003
52
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
159.9
319.6
484.2
Symbols on linear scale
Figure 33. continued
53
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
280.0
559.9
53°
848.3
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 34. Concentration of sprat (Sprattus sprattus) larvae (nos.m-2) in 2001
54
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
38.6
77.2
116.9
Symbols on linear scale
Figure 35. Concentration of sprat (Sprattus sprattus) larvae (nos.m-2) in 2002
55
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 36. Concentration of sprat (Sprattus sprattus) larvae (nos.m-2) in 2003
56
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
25.9
51.7
78.2
Symbols on linear scale
Figure 36. continued
57
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
12.4
24.7
53°
37.4
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 37. Concentration of late-stage cod (Gadus morhua) eggs (nos.m-2) in 2001
58
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
11.3
22.4
33.9
Symbols on linear scale
Figure 38. Concentration of late-stage cod (Gadus morhua) eggs (nos.m-2) in 2002
59
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 39. Concentration of late-stage cod (Gadus morhua) eggs (nos.m-2) in 2003
60
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
2.7
5.4
8.1
Symbols on linear scale
Figure 39. continued
61
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
4.8
9.5
53°
14.4
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 40. Concentration of cod (Gadus morhua) larvae (nos.m-2) in 2001
62
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
1.8
3.6
5.4
Symbols on linear scale
Figure 41. Concentration of cod (Gadus morhua) larvae (nos.m-2) in 2002
63
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 42. Concentration of cod (Gadus morhua) larvae (nos.m-2) in 2003
64
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
7.2
14.3
21.7
Symbols on linear scale
Figure 42. continued
65
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
0.3
0.5
53°
0.7
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 43. Concentration of late-stage haddock (Melanogrammus aeglefinus) eggs (nos.m-2) in 2001
66
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
0.3
0.5
0.7
Symbols on linear scale
Figure 44. Concentration of late-stage haddock (Melanogrammus aeglefinus) eggs (nos.m-2) in 2002
67
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 45. Concentration of late-stage haddock (Melanogrammus aeglefinus) eggs (nos.m-2) in 2003
68
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
0.2
0.2
0.3
Symbols on linear scale
Figure 45. continued
69
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.0
1.9
53°
2.8
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 46. Concentration of haddock (Melanogrammus aeglefinus) larvae (nos.m-2) in 2001
70
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
1.8
3.5
5.2
Symbols on linear scale
Figure 47. Concentration of haddock (Melanogrammus aeglefinus) larvae (nos.m-2) in 2002
71
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 48. Concentration of haddock (Melanogrammus aeglefinus) larvae (nos.m-2) in 2003
72
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
1.7
3.2
4.8
Symbols on linear scale
Figure 48. continued
73
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
31.8
63.6
53°
96.3
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 49. Concentration of whiting (Merlangius merlangus) larvae (nos.m-2) in 2001
74
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
21.3
42.6
64.5
Symbols on linear scale
Figure 50. Concentration of whiting (Merlangius merlangus) larvae (nos.m-2) in 2002
75
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 51. Concentration of whiting (Merlangius merlangus) larvae (nos.m-2) in 2003
76
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
42.2
84.3
127.7
Symbols on linear scale
Figure 51. continued
77
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
3.8
7.5
53°
11.4
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 52. Concentration of Norway pout and poor cod (Gadidae) larvae (nos.m-2) in 2001
78
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
1.0
1.9
2.8
Symbols on linear scale
Figure 53. Concentration of Norway pout and poor cod (Gadidae) larvae (nos.m-2) in 2002
79
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 54. Concentration of Norway pout and poor cod (Gadidae) larvae (nos.m-2) in 2003
80
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
9.1
18.2
27.5
Symbols on linear scale
Figure 54. continued
81
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
8.2
16.4
53°
24.8
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 55. Concentration of bib (Trisopterus luscus) larvae (nos.m-2) in 2001
82
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
2.6
5.0
7.5
Symbols on linear scale
Figure 56. Concentration of bib (Trisopterus luscus) larvae (nos.m-2) in 2002
83
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 57. Concentration of bib (Trisopterus luscus) larvae (nos.m-2) in 2003
84
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
12.5
24.9
37.7
Symbols on linear scale
Figure 57. continued
85
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.3
2.5
53°
3.8
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 58. Concentration of pollack (Pollachius pollachius) larvae (nos.m-2) in 2001
86
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
1.5
3.0
4.5
Symbols on linear scale
Figure 59. Concentration of pollack (Pollachius pollachius) larvae (nos.m-2) in 2002
87
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
3°
6°
5°
Figure 60. Concentration of pollack (Pollachius pollachius) larvae (nos.m-2) in 2003
88
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
1.0
2.0
3.0
Symbols on linear scale
Figure 60. continued
89
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
14.4
28.6
53°
43.4
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 61. Concentration of rockling (Gadidae) eggs (nos.m-2) in 2001
90
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
40.1
80.1
121.3
Symbols on linear scale
Figure 62. Concentration of rockling (Gadidae) eggs (nos.m-2) in 2002
91
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 63. Concentration of rockling (Gadidae) eggs (nos.m-2) in 2003
92
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
30.8
61.6
93.2
Symbols on linear scale
Figure 63. continued
93
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
7.6
15.1
53°
22.8
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 64. Concentration of rockling (Gadidae) larvae (nos.m-2) in 2001
94
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
5.9
11.6
17.5
Symbols on linear scale
Figure 65. Concentration of rockling (Gadidae) larvae (nos.m-2) in 2002
95
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 66. Concentration of rockling (Gadidae) larvae (nos.m-2) in 2003
96
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
10.0
19.9
30.1
Symbols on linear scale
Figure 66. continued
97
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.4
2.6
53°
3.9
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 67. Concentration of ling (Molva molva) eggs (nos.m-2) in 2001
98
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
0.9
1.8
2.7
Symbols on linear scale
Figure 68. Concentration of ling (Molva molva) eggs (nos.m-2) in 2002
99
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 69. Concentration of ling (Molva molva) eggs (nos.m-2) in 2003
100
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
1.2
2.4
3.5
Symbols on linear scale
Figure 69. continued
101
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.5
2.9
53°
4.4
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 70. Concentration of ling (Molva molva) larvae (nos.m-2) in 2001
102
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
0.4
0.7
1.0
Symbols on linear scale
Figure 71. Concentration of ling (Molva molva) larvae (nos.m-2) in 2002
103
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 72. Concentration of ling (Molva molva) larvae (nos.m-2) in 2003
104
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
0.4
0.7
1.0
Symbols on linear scale
Figure 72. continued
105
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
2.0
3.9
53°
5.9
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 73. Concentration of gurnard (Triglidae) eggs (nos.m-2) in 2001
106
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
14.1
28.1
42.5
Symbols on linear scale
Figure 74. Concentration of gurnard (Triglidae) eggs (nos.m-2) in 2002
107
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 75. Concentration of gurnard (Triglidae) eggs (nos.m-2) in 2003
108
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
11.7
23.3
35.3
Symbols on linear scale
Figure 75. continued
109
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.5
2.8
53°
4.2
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 76. Concentration of Cottidae larvae (nos.m-2) in 2001
110
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
2.9
5.6
8.5
Symbols on linear scale
Figure 77. Concentration of Cottidae larvae (nos.m-2) in 2002
111
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 78. Concentration of Cottidae larvae (nos.m-2) in 2003
112
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
2.0
3.9
5.9
Symbols on linear scale
Figure 78. continued
113
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
0.5
0.9
53°
1.3
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 79. Concentration of pogge (Agonus cataphractus) larvae (nos.m-2) in 2001
114
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
0.3
0.5
0.7
Symbols on linear scale
Figure 80. Concentration of pogge (Agonus cataphractus) larvae (nos.m-2) in 2002
115
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 81. Concentration of pogge (Agonus cataphractus) larvae (nos.m-2) in 2003
116
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
1.0
1.9
2.8
Symbols on linear scale
Figure 81. continued
117
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
5.0
10.0
53°
15.1
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 82. Concentration of sea snail (Liparis spp.) larvae (nos.m-2) in 2001
118
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
4.5
8.8
13.4
Symbols on linear scale
Figure 83. Concentration of sea snail (Liparis spp.) larvae (nos.m-2) in 2002
119
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 84. Concentration of sea snail (Liparis spp.) larvae (nos.m-2) in 2003
120
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
3.1
6.2
9.3
Symbols on linear scale
Figure 84. continued
121
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
0.5
1.0
53°
1.5
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 85. Concentration of Yarrell's blenny (Chirolophis ascanii) larvae (nos.m-2) in 2001
122
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
0.4
0.7
1.0
Symbols on linear scale
Figure 86. Concentration of Yarrell's blenny (Chirolophis ascanii) larvae (nos.m-2) in 2002
123
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 87. Concentration of Yarrell's blenny (Chirolophis ascanii) larvae (nos.m-2) in 2003
124
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
0.3
0.5
0.7
Symbols on linear scale
Figure 87. continued
125
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
6.1
12.1
53°
18.3
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 88. Concentration of butterfish (Pholis gunnellus) larvae (nos.m-2) in 2001
126
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
4.9
9.8
14.7
Symbols on linear scale
Figure 89. Concentration of butterfish (Pholis gunnellus) larvae (nos.m-2) in 2002
127
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 90. Concentration of butterfish (Pholis gunnellus) larvae (nos.m-2) in 2003
128
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
5.6
11.0
16.6
Symbols on linear scale
Figure 90. continued
129
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
79.1
158.0
53°
239.3
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 91. Concentration of sandeel (Ammodytidae) larvae (nos.m-2) in 2001
130
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
24.8
49.6
75.1
Symbols on linear scale
Figure 92. Concentration of sandeel (Ammodytidae) larvae (nos.m-2) in 2002
131
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 93. Concentration of sandeel (Ammodytidae) larvae (nos.m-2) in 2003
132
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
35.6
71.0
107.5
Symbols on linear scale
Figure 93. continued
133
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
74.2
148.3
53°
224.6
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 94. Concentration of dragonet (Callionymidae) eggs (nos.m-2) in 2001
134
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
73.7
147.3
223.2
Symbols on linear scale
Figure 95. Concentration of dragonet (Callionymidae) eggs (nos.m-2) in 2002
135
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 96. Concentration of dragonet (Callionymidae) eggs (nos.m-2) in 2003
136
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
59.6
119.0
180.3
Symbols on linear scale
Figure 96. continued
137
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
42.8
85.4
53°
129.4
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 97. Concentration of dragonet (Callionymidae) larvae (nos.m-2) in 2001
138
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
32.4
64.7
98.0
Symbols on linear scale
Figure 98. Concentration of dragonet (Callionymidae) larvae (nos.m-2) in 2002
139
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 99. Concentration of dragonet (Callionymidae) larvae (nos.m-2) in 2003
140
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
25.7
51.4
77.8
Symbols on linear scale
Figure 99. continued
141
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
3.6
7.0
53°
10.6
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 100. Concentration of Gobiidae spp. larvae (nos.m-2) in 2001
142
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
31.7
63.3
95.9
Symbols on linear scale
Figure 101. Concentration of Gobiidae spp. larvae (nos.m-2) in 2002
143
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 102. Concentration of Gobiidae spp. larvae (nos.m-2) in 2003
144
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
4.0
7.8
11.8
Symbols on linear scale
Figure 102. continued
145
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
3.1
6.1
53°
9.1
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 103. Concentration of Norwegian topknot (Phrynorhombus norvegicus) eggs (nos.m-2) in 2001
146
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
7.8
15.5
23.5
Symbols on linear scale
Figure 104. Concentration of Norwegian topknot (Phrynorhombus norvegicus) eggs (nos.m-2) in 2002
147
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 105. Concentration of Norwegian topknot (Phrynorhombus norvegicus) eggs (nos.m-2) in 2003
148
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
3.3
6.5
9.8
Symbols on linear scale
Figure 105. continued
149
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
0.9
1.8
53°
2.7
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 106. Concentration of Norwegian topknot (Phrynorhombus norvegicus) larvae (nos.m-2) in 2001
150
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
0.3
0.5
0.8
Symbols on linear scale
Figure 107. Concentration of Norwegian topknot (Phrynorhombus norvegicus) larvae (nos.m-2) in 2002
151
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 108. Concentration of Norwegian topknot (Phrynorhombus norvegicus) larvae (nos.m-2) in 2003
152
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
4.3
8.5
12.8
Symbols on linear scale
Figure 108. continued
153
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
2.3
4.6
53°
6.9
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 109. Concentration of topknot (Zeugopterus punctatus) eggs (nos.m-2) in 2001
154
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
2.5
5.0
7.5
Symbols on linear scale
Figure 110. Concentration of topknot (Zeugopterus punctatus) eggs (nos.m-2) in 2002
155
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 111. Concentration of topknot (Zeugopterus punctatus) eggs (nos.m-2) in 2003
156
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
1.5
2.9
4.4
Symbols on linear scale
Figure 111. continued
157
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.2
2.2
53°
3.3
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 112. Concentration of topknot (Zeugopterus punctatus) larvae (nos.m-2) in 2001
158
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
1.2
2.3
3.5
Symbols on linear scale
Figure 113. Concentration of topknot (Zeugopterus punctatus) larvae (nos.m-2) in 2002
159
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 114. Concentration of topknot (Zeugopterus punctatus) larvae (nos.m-2) in 2003
160
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
1.1
2.0
3.0
Symbols on linear scale
Figure 114. continued
161
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
61.1
122.2
53°
185.0
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 115. Concentration of plaice (Pleuronectes platessa) eggs (nos.m-2) in 2001
162
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
70.1
140.2
212.3
Symbols on linear scale
Figure 116. Concentration of plaice (Pleuronectes platessa) eggs (nos.m-2) in 2002
163
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 117. Concentration of plaice (Pleuronectes platessa) eggs (nos.m-2) in 2003
164
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
67.2
134.2
203.3
Symbols on linear scale
Figure 117. continued
165
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
15.6
31.2
53°
47.2
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 118. Concentration of plaice (Pleuronectes platessa) larvae (nos.m-2) in 2001
166
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
23.6
47.0
71.2
Symbols on linear scale
Figure 119. Concentration of plaice (Pleuronectes platessa) larvae (nos.m-2) in 2002
167
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 120. Concentration of plaice (Pleuronectes platessa) larvae (nos.m-2) in 2003
168
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
11.0
21.9
33.1
Symbols on linear scale
Figure 120. continued
169
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
165.6
331.2
53°
501.8
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 121. Concentration of flounder (Platichthys flesus) larvae (nos.m-2) in 2001
170
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
31.2
62.2
94.2
Symbols on linear scale
Figure 122. Concentration of flounder (Platichthys flesus) larvae (nos.m-2) in 2002
171
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 123. Concentration of flounder (Platichthys flesus) larvae (nos.m-2) in 2003
172
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
88.0
175.8
266.4
Symbols on linear scale
Figure 123. continued
173
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
403.4
806.6
53°
1222.1
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 124. Concentration of dab (Limanda limanda) larvae (nos.m-2) in 2001
174
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
85.3
170.4
258.1
Symbols on linear scale
Figure 125. Concentration of dab (Limanda limanda) larvae (nos.m-2) in 2002
175
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 126. Concentration of dab (Limanda limanda) larvae (nos.m-2) in 2003
176
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
230.2
460.2
697.3
Symbols on linear scale
Figure 126. continued
177
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
0.3
0.4
53°
0.6
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 127. Concentration of late-stage lemon sole (Microstomus kitt) eggs (nos.m-2) in 2001
178
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
0.3
0.5
0.7
Symbols on linear scale
Figure 128. Concentration of late-stage lemon sole (Microstomus kitt) eggs (nos.m-2) in 2002
179
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 129. Concentration of late-stage lemon sole (Microstomus kitt) eggs (nos.m-2) in 2003
180
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
0.3
0.6
0.8
Symbols on linear scale
Figure 129. continued
181
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
0.9
1.8
53°
2.7
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 130. Concentration of lemon sole (Microstomus kitt) larvae (nos.m-2) in 2001
182
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
1.0
1.9
2.8
Symbols on linear scale
Figure 131. Concentration of lemon sole (Microstomus kitt) larvae (nos.m-2) in 2002
183
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 132. Concentration of lemon sole (Microstomus kitt) larvae (nos.m-2) in 2003
184
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
0.4
0.7
1.0
Symbols on linear scale
Figure 132. continued
185
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.4
2.8
53°
4.1
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 133. Concentration of witch (Glyptocephalus cynoglossus) larvae (nos.m-2) in 2001
186
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
1.1
2.1
3.1
Symbols on linear scale
Figure 134. Concentration of witch (Glyptocephalus cynoglossus) larvae (nos.m-2) in 2002
187
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 135. Concentration of witch (Glyptocephalus cynoglossus) larvae (nos.m-2) in 2003
188
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
1.6
3.0
4.6
Symbols on linear scale
Figure 135. continued
189
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
14.1
28.0
53°
42.4
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 136. Concentration of sole (Solea solea) eggs (nos.m-2) in 2001
190
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
24.3
48.4
73.3
Symbols on linear scale
Figure 137. Concentration of sole (Solea solea) eggs (nos.m-2) in 2002
191
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 138. Concentration of sole (Solea solea) eggs (nos.m-2) in 2003
192
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
40.5
81.0
122.6
Symbols on linear scale
Figure 138. continued
193
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
4°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
5.5
10.9
53°
16.5
52°
Symbols on linear scale
6°
6°
5°
5°
4°
4°
3°
3°
Figure 139. Concentration of sole (Solea solea) larvae (nos.m-2) in 2001
194
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
5°
55°
54°
54°
53°
53°
6°
5°
3°
30 April - 2 May
8 - 10 April
55°
52°
4°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
7.5
14.9
22.6
Symbols on linear scale
Figure 140. Concentration of sole (Solea solea) larvae (nos.m-2) in 2002
195
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
Figure 141. Concentration of sole (Solea solea) larvae (nos.m-2) in 2003
196
5°
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
6.1
12.1
18.3
Symbols on linear scale
Figure 141. continued
197
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
8.6
17.1
53°
25.9
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 142. Concentration of solenette (Buglossidium luteum) eggs (nos.m-2) in 2001
198
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
56.8
113.6
172.0
Symbols on linear scale
Figure 143. Concentration of solenette (Buglossidium luteum) eggs (nos.m-2) in 2002
199
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 144. Concentration of solenette (Buglossidium luteum) eggs (nos.m-2) in 2003
200
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
63.8
127.6
193.3
Symbols on linear scale
Figure 144. continued
201
29 January - 1 February
26 February - 2 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
4°
3°
4°
3°
2 - 5 April
19 - 23 March
55°
52°
5°
52°
3°
6°
5°
23 - 26 April
55°
Symbol Nos.m-2
0.1
54°
1.5
3.0
53°
4.5
Symbols on linear scale
52°
6°
6°
5°
5°
4°
4°
3°
3°
Figure 145. Concentration of solenette (Buglossidium luteum) larvae (nos.m-2) in 2001
202
19 - 21 February
13 - 16 March
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
6°
55°
54°
54°
53°
53°
6°
5°
4°
3°
30 April - 2 May
8 - 10 April
55°
52°
5°
4°
52°
3°
6°
5°
4°
Symbol Nos.m-2
0.1
4.3
8.4
12.7
Symbols on linear scale
Figure 146. Concentration of solenette (Buglossidium luteum) larvae (nos.m-2) in 2002
203
3°
13 - 17 January
3 - 6 February
55°
55°
54°
54°
53°
53°
52°
6°
5°
4°
52°
3°
55°
54°
54°
53°
53°
6°
5°
4°
52°
3°
6°
17 - 19 March
4°
3°
5°
4°
3°
4°
3°
12 - 15 April
55°
55°
54°
54°
53°
53°
52°
5°
26 February - 1 March
19 - 24 February
55°
52°
6°
52°
6°
5°
4°
6°
3°
5°
Figure 147. Concentration of solenette (Buglossidium luteum) larvae (nos.m-2) in 2003
204
28 - 30 April
55°
54°
53°
52°
6°
5°
4°
3°
Symbol Nos.m-2
0.1
5.0
9.9
14.9
Symbols on linear scale
Figure 147. continued
205
Table 2a.
List of identified species occurring as eggs and the maximum concentration on each of the surveys in the eastern Irish Sea in 2001, 2002 and 2003.
Species marked * have been plotted
Species
2001
2002
29 Jan1 Feb
26 Feb2 Mar
19-23 Mar 2-5 Apr
Sprattus sprattus*
1.3
825.7
304.7
Sardina pilchardus
-
-
-
Engraulis encrasicolus
-
-
-
Argentina sphyraena
-
-
-
Gadus morhua+*
0.6
25.4
Melanogrammus aeglefinus+*
-
Gadidae (rocklings)*
1.0
Molva molva*
Triglidae*
2003
206
23-26 Apr 19-21 Feb 13-16 Mar 8-10 Apr
30 Apr2 May
13-17 Jan 3-6 Feb
19-24 Feb 26 Feb1 Mar
17-19 Mar 12-15 Apr 28-30 Apr
696.5
460.8
69.8
534.4
375.6
309.6
-
17.5
23.3
28.2
105.8
484.2
445.4
-
-
-
-
1.8
-
-
-
-
-
-
-
-
0.8
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1.1
-
-
-
-
-
-
-
37.4
22.8
4.4
8.8
33.9
10.6
1.7
-
1.7
3.1
2.4
8.1
1.6
-
-
0.7
-
-
-
0.7
-
-
-
-
0.1
0.3
-
-
-
11.7
42.7
43.4
21.1
12.1
71.8
62.3
121.3
1.7
5.8
13.7
28.2
39.3
53.0
93.2
-
-
2.2
-
3.9
-
-
1.6
2.7
-
0.5
0.1
0.1
0.3
3.5
-
-
-
0.8
3.3
5.9
0.3
2.2
33.3
42.5
-
-
0.2
0.2
2.5
6.5
35.3
Dicentrarchus labrax
-
-
-
-
-
-
-
-
3.2
-
-
-
-
-
-
-
Echiichthys vipera
-
-
2.8
-
-
-
-
-
2.8
-
-
-
-
-
-
-
Ammodytidae
-
-
-
-
-
-
-
-
-
-
-
-
0.8
-
-
15.1
Callionymiidae*
0.8
150.3
175.2
170.8
224.6
52.5
80.0
223.2
154.0
5.6
2.5
44.6
52.1
180.3
148.9
125.1
Phrynorhombus norvegicus*
-
-
3.6
4.4
9.1
-
0.7
23.5
11.3
-
0.3
0.7
0.2
4.1
4.3
9.8
Zeugopterus punctatus*
-
0.9
0.7
4.4
6.9
-
-
7.5
1.5
-
-
-
-
1.3
2.2
4.4
Arnoglossus laterna
-
-
-
-
1.1
-
0.9
1.2
0.9
-
-
-
-
-
-
-
Pleuronectes platessa*
29.2
185.0
60.1
34.5
0.7
212.3
83.8
30.3
1.1
12.7
119.6
203.3
133.5
165.9
12.4
4.8
Platichthys flesus
-
-
-
-
-
-
0.9
-
-
-
-
-
-
-
-
-
Microstomus kitt+*
-
-
0.6
-
-
-
-
0.7
-
-
0.8
-
-
-
-
-
Hippoglossoides platessoides
-
0.1
1.8
-
-
-
-
0.6
-
-
-
0.1
-
-
-
-
Solea solea*
-
3.0
32.1
28.0
42.4
5.4
27.7
61.0
73.3
-
1.1
2.2
2.2
23.2
122.6
85.8
Buglossidium luteum*
-
1.7
1.4
0.5
25.9
0.8
4.0
15.0
172.0
-
0.3
0.8
0.8
18.2
6.0
193.3
Microchirus variegatus
-
-
-
-
-
-
-
3.0
8.5
-
-
-
-
-
0.4
4.4
Unidentified spp.
93.2
3330.4
2641.9
1005.5
169.9
1168.1
2806.6
1564.3
502.0
5.7
686.2
2902.6
2205.4
7722.1
1433.4
179.0
Total number of stations worked
49
47
46
37
48
11
49
49
49
27
30
48
47
49
49
41
+ late-stage eggs only (stages IV and V)
Table 2b.
List of identified species occurring as larvae and the maximum concentration on each of the surveys in the eastern Irish Sea in 2001, 2002 and 2003.
Species marked * have been plotted
Species
207
Clupeidae
Clupea harengus*
Sprattus sprattus*
Sardina pilchardus
Gobiesocidae
Gadus morhua*
Melanogrammus aeglefinus*
Merlangius merlangus*
Micromesistius poutassou
Gadidae*†
Trisopterus minutus†
Trisopterus esmarkii†
Trisopterus luscus*
Pollachius pollachius*
Gadidae* (rocklings)
Molva molva*
Syngnathidae
Triglidae
Cottidae*‡
Myoxocephalus scorpius‡
Taurulus bubalis‡
Agonus cataphractus*
Liparis spp.*
Trachurus trachurus
Labrus bergylta
Chirolophis ascanii*
Pholis gunnellus*
Ammodytidae*
Callionymiidae*
Gobiidae*
† plotted together as Gadidae
‡ plotted together as Cottidae
2001
2002
2003
29 Jan1 Feb
26 Feb2 Mar
19-23 Mar 2-5 Apr
23-26 Apr 19-21 Feb 13-16 Mar 8-10 Apr
30 Apr2 May
13-17 Jan 3-6 Feb
19-24 Feb 26 Feb1 Mar
17-19 Mar 12-15 Apr 28-30 Apr
0.4
9.0
0.4
1.2
2.1
23.3
4.7
17.1
0.1
6.2
1.2
0.9
0.1
0.1
0.1
0.7
3.7
1.6
1.3
2.2
157.9
7.1
2.8
96.3
4.5
8.3
2.8
4.5
0.9
1.0
1.1
1.3
3.0
1.2
16.4
68.5
21.8
1.3
848.3
14.4
1.8
69.1
1.6
3.4
1.6
24.8
3.7
20.6
4.4
3.5
2.9
4.2
1.1
9.0
1.5
10.1
239.3
129.4
10.6
116.9
0.6
57.9
2.3
2.8
0.5
7.5
4.5
17.5
1.0
0.8
3.8
8.5
0.6
13.4
0.9
5.5
31.2
98.0
95.9
2.6
3.1
0.3
31.0
0.1
0.6
9.3
0.6
0.4
0.4
0.2
0.4
0.3
0.1
0.5
3.8
3.0
1.5
0.7
2.1
14.9
0.5
9.3
2.7
107.7
25.1
19.2
37.7
0.7
4.4
0.4
0.5
0.3
0.6
2.4
0.7
2.2
83.7
16.1
1.2
1.1
345.0
11.6
1.1
32.9
6.4
15.2
3.8
22.8
2.9
3.3
0.5
1.0
15.1
18.3
95.8
59.1
1.0
0.9
1.6
0.5
1.6
0.8
0.7
0.7
1.7
0.8
74.3
0.4
5.4
64.5
2.9
0.7
2.1
2.3
0.6
0.6
3.7
0.7
14.7
32.1
14.9
0.5
2.2
114.2
1.2
5.2
5.2
39.4
2.0
5.9
0.8
12.7
2.2
0.7
7.4
0.7
1.0
10.1
75.1
22.5
3.4
8.9
1.0
11.8
1.0
1.2
0.1
3.4
2.6
0.7
1.5
0.7
9.8
2.2
1.2
2.2
3.6
0.6
0.3
0.2
0.1
0.6
0.3
0.3
3.0
7.1
1.2
2.1
61.8
21.7
0.7
127.7
0.6
6.1
2.0
1.4
8.4
1.0
2.1
4.2
3.0
2.8
6.0
0.6
5.2
74.3
29.5
2.8
3.7
78.2
5.5
4.8
48.1
3.0
4.2
3.0
30.1
0.5
0.8
4.2
5.9
0.6
9.3
0.6
16.6
39.5
77.8
11.8
Table 2b.
continued
Species
2001
2002
2003
208
29 Jan1 Feb
26 Feb2 Mar
19-23 Mar 2-5 Apr
23-26 Apr 19-21 Feb 13-16 Mar 8-10 Apr
30 Apr2 May
13-17 Jan 3-6 Feb
19-24 Feb 26 Feb1 Mar
17-19 Mar 12-15 Apr 28-30 Apr
Phrynorhombus norvegicus*
-
-
-
-
2.7
-
-
-
0.8
-
-
-
-
-
2.1
12.8
Zeugopterus punctatus*
-
-
-
-
3.3
-
-
3.5
1.0
-
-
-
-
-
1.4
3.0
Pleuronectes platessa*
0.4
15.6
24.8
47.2
14.6
2.9
19.8
34.4
71.2
0.5
7.2
18.6
7.5
18.3
19.6
33.1
Platichthys flesus*
-
129.1
225.6
501.8
243.5
4.1
94.2
68.9
60.3
-
2.5
9.9
18.3
133.9
137.5
266.4
Limanda limanda*
-
20.2
530.0
542.1
1222.1
1.1
188.4
182.9
258.1
0.7
4.4
24.2
8.4
146.2
697.3
671.6
Microstomus kitt*
-
-
2.2
-
2.7
-
-
-
2.8
-
-
-
-
0.6
-
1.0
Glyptocephalus cynoglossus*
0.4
-
1.2
0.5
4.1
-
0.5
3.1
2.8
-
-
-
0.1
1.8
3.0
4.6
Soleidae
-
-
-
-
-
-
-
-
0.9
-
-
-
-
-
-
-
Solea solea*
-
1.0
0.6
3.9
16.5
-
0.9
3.2
22.6
-
-
-
-
-
3.0
18.3
Buglossidium luteum*
-
-
4.5
-
3.7
-
-
7.4
12.7
-
-
-
-
0.6
14.9
8.1
Microchirus variegatus
-
-
-
-
-
-
-
-
0.9
-
-
-
-
-
1.1
0.8
Unidentified spp.
-
49.8
85.1
75.6
25.1
1.5
55.6
34.9
18.9
0.8
8.5
10.5
10.3
105.6
20.1
4.9
Total number of stations worked
49
47
46
37
48
11
49
49
49
27
30
48
47
49
49
41
Table 2c.
List of identified species occurring as eggs and their frequency on each of the surveys in the eastern Irish Sea in 2001, 2002 and 2003
Species
2001
2002
2003
29 Jan1 Feb
26 Feb2 Mar
19-23 Mar 2-5 Apr
23-26 Apr 19-21 Feb 13-16 Mar 8-10 Apr
30 Apr2 May
13-17 Jan 3-6 Feb
19-24 Feb 26 Feb1 Mar
17-19 Mar 12-15 Apr 28-30 Apr
Sprattus sprattus
4.1
78.7
91.3
91.9
93.8
72.7
91.8
95.9
95.9
-
26.7
75.0
63.8
89.8
98.0
95.1
Sardina pilchardus
-
-
-
-
-
-
-
2.0
-
-
-
-
-
-
-
-
Engraulis encrasicolus
-
-
-
2.7
-
-
-
-
-
-
-
-
-
-
-
-
Argentina sphyraena
-
-
-
-
-
-
-
-
2.0
-
-
-
-
-
-
-
Gadus morhua+
2.0
42.6
39.1
32.4
8.3
9.1
38.8
53.1
18.4
-
3.3
43.8
40.4
36.7
20.4
-
Melanogrammus aeglefinus+
-
-
2.2
-
-
-
2.0
-
-
-
-
4.2
2.1
-
-
-
Gadidae spp. (rocklings)
16.3
59.6
84.8
70.3
83.3
63.6
83.7
98.0
93.9
18.5
50.0
72.9
78.7
81.6
87.8
92.7
Molva molva
-
-
2.2
-
4.2
-
-
8.2
6.1
-
3.3
2.1
2.1
2.0
4.1
56.1
209
Trigla spp.
-
-
6.5
13.5
12.5
9.1
12.2
36.7
40.8
-
-
8.3
2.1
4.1
36.7
Dicentrarchus labrax
-
-
-
-
-
-
-
-
6.1
-
-
-
-
-
-
-
Echiichthys vipera
-
-
6.5
-
-
-
-
-
8.2
-
-
-
-
-
-
-
Ammodytidae
-
-
-
-
-
-
-
-
-
-
-
-
2.1
-
-
2.4
Callionymiidae
8.2
74.5
93.5
94.6
91.7
18.2
77.6
93.9
95.9
14.8
20.0
62.5
63.8
87.8
98.0
95.1
Phrynorhombus norvegicus
-
-
6.5
13.5
18.8
-
2.0
8.2
46.9
-
3.3
4.2
2.1
20.4
38.8
48.8
Zeugopterus punctatus
-
2.1
2.2
8.1
14.6
-
-
20.4
10.2
-
-
-
-
2.0
10.2
22.0
Arnoglossus laterna
-
-
-
-
2.1
-
6.1
2.0
2.0
-
-
-
-
-
-
-
Pleuronectes platessa
71.4
87.2
84.8
54.1
4.2
81.8
77.6
71.4
6.1
70.4
83.3
93.8
97.9
91.8
53.1
7.3
Platichthys flesus
-
-
-
-
-
-
2.0
-
-
-
-
-
-
-
-
-
Microstomus kitt+
-
-
2.2
-
-
-
-
2.0
-
-
3.3
-
-
-
-
-
Hippoglossoides platessoides
-
2.1
2.2
-
-
-
-
2.0
-
-
-
2.1
-
-
-
-
Solea solea
-
44.7
65.2
70.3
77.1
45.5
51.0
85.7
91.8
-
6.7
45.8
21.3
71.4
85.7
65.9
Buglossidium luteum
-
6.4
10.9
2.7
43.8
18.2
10.2
36.7
75.5
-
3.3
14.6
17.0
10.2
36.7
61.0
Microchirus variegatus
-
-
-
-
-
-
-
4.1
14.3
-
-
-
-
-
4.1
12.2
Unidentified spp.
73.5
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
63.0
90.0
100.0
100.0
100.0
100.0
100.0
Total number of stations worked
49
47
46
37
48
11
49
49
49
27
30
48
47
49
49
41
+ late-stage eggs only (stages IV and V)
Table 2d.
List of identified species occurring as larvae and their frequency on each of the surveys in the eastern Irish Sea in 2001, 2002 and 2003
Species
2001
2002
2003
210
29 Jan1 Feb
26 Feb2 Mar
19-23 Mar 2-5 Apr
23-26 Apr 19-21 Feb 13-16 Mar 8-10 Apr
30 Apr2 May
13-17 Jan 3-6 Feb
19-24 Feb 26 Feb1 Mar
17-19 Mar 12-15 Apr 28-30 Apr
Clupeidae
2.0
-
-
-
-
18.2
2.0
4.1
-
-
-
2.1
4.3
2.0
-
-
Clupea harengus
32.7
12.8
10.9
8.1
-
27.3
10.2
-
-
40.7
23.3
66.7
51.1
10.2
8.2
7.3
Sprattus sprattus
2.0
68.1
84.8
97.3
100.0
-
67.3
98.0
100.0
-
-
2.1
12.8
71.4
95.9
100.0
Sardina pilchardus
-
-
-
-
-
-
2.0
8.2
-
-
-
-
-
2.0
-
-
Gobiesocidae
-
-
-
-
-
-
-
-
-
-
-
-
0.7
-
-
-
Gadus morhua
-
25.5
30.4
37.8
29.2
-
8.2
44.9
4.1
-
6.7
41.7
48.9
69.4
69.4
22.0
Melanogrammus aeglefinus
-
-
4.3
5.4
2.1
-
-
2.0
-
-
-
-
2.1
10.2
4.1
9.8
Merlangius merlangus
-
36.2
58.7
78.4
97.9
18.2
59.2
85.7
87.8
-
26.7
75.0
68.1
79.6
95.9
97.6
Micromesistius poutassou
-
-
-
-
4.2
-
-
-
-
-
-
-
-
-
-
-
Gadidae
-
2.1
6.5
13.5
10.4
-
-
10.2
4.1
-
-
2.1
4.3
-
2.0
7.3
Trisopterus minutus
-
-
-
-
2.1
-
-
-
2.0
-
-
-
2.1
20.4
-
-
Trisopterus esmarkii
-
-
-
-
-
-
-
-
2.0
-
-
-
-
36.7
20.4
-
Trisopterus luscus
-
27.7
41.3
48.6
43.8
18.2
6.1
46.9
36.7
-
-
16.7
21.3
49.0
18.4
29.3
Pollachius pollachius
-
2.1
4.3
2.7
18.8
-
2.0
2.0
6.1
-
-
2.1
-
2.0
4.1
7.3
Gadidae (rocklings)
-
2.1
19.6
43.2
54.2
-
24.5
59.2
71.4
-
-
14.6
19.1
51.0
67.3
68.3
Molva molva
-
-
-
-
2.1
-
-
-
4.1
-
-
-
-
-
4.1
-
Syngnathidae
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
2.4
Trigla spp.
-
-
-
-
-
-
-
-
4.1
-
-
-
-
2.0
-
2.4
Cottidae
-
4.3
10.9
21.6
12.5
-
10.2
20.4
8.2
-
-
22.9
21.3
4.1
16.3
24.4
Myoxocephalus scorpius
-
4.3
10.9
8.1
10.4
-
2.0
-
-
-
-
-
8.5
-
12.2
9.8
Taurulus bubalis
-
-
8.7
2.7
4.2
-
-
-
12.2
-
-
-
2.1
2.0
8.2
2.4
Agonus cataphractus
-
2.1
6.5
8.1
4.2
-
2.0
12.2
2.0
-
-
-
2.1
2.0
8.2
-
Liparis spp.
-
-
28.3
29.7
22.9
9.1
24.5
51.0
30.6
-
-
20.8
21.3
32.7
51.0
31.7
Trachurus trachurus
-
-
-
-
-
-
-
4.1
-
-
-
-
-
-
-
-
Labrus bergylta
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
2.4
Chirolophis ascanii
-
-
2.2
-
2.1
-
2.0
2.0
2.0
-
-
6.3
4.3
4.1
4.1
-
Pholis gunnellus
-
8.5
50.0
48.6
35.4
-
32.7
36.7
28.6
-
-
6.3
12.8
6.1
20.4
43.9
Ammodytidae
-
17.0
58.7
86.5
70.8
-
61.2
91.8
77.6
-
-
12.5
12.8
67.3
89.8
73.2
Callionymiidae
-
21.3
52.2
89.2
91.7
27.3
30.6
63.3
85.7
-
6.7
25.0
34.0
46.9
71.4
100.0
Gobiiidae
8.2
10.6
8.7
2.7
37.5
9.1
2.0
30.6
73.5
7.4
10.0
14.6
34.0
16.3
20.4
75.6
Table 2d. continued
Species
2001
2002
2003
211
29 Jan1 Feb
26 Feb2 Mar
19-23 Mar 2-5 Apr
23-26 Apr 19-21 Feb 13-16 Mar 8-10 Apr
30 Apr2 May
13-17 Jan 3-6 Feb
19-24 Feb 26 Feb1 Mar
17-19 Mar 12-15 Apr 28-30 Apr
Phrynorhombus norvegicus
-
-
-
-
2.1
-
-
-
2.0
-
-
-
-
Zeugopterus punctatus
-
-
-
-
10.4
-
-
10.2
6.1
-
-
-
-
-
2.0
7.3
Pleuronectes platessa
4.1
51.1
71.7
78.4
31.3
54.5
44.9
71.4
63.3
3.7
33.3
52.1
70.2
77.6
36.7
34.1
Platichthys flesus
-
40.4
80.4
94.6
95.8
27.3
51.0
89.8
81.6
-
3.3
47.9
72.3
81.6
100.0
100.0
Limanda limanda
-
61.7
91.3
100.0
97.9
9.1
77.6
98.0
98.0
7.4
26.7
89.6
76.6
87.8
100.0
97.6
Microstomus kitt
-
-
2.2
-
2.1
-
-
-
10.2
-
-
-
-
2.0
-
9.8
Glyptocephalus cynoglossus
2.0
-
2.2
5.4
10.4
-
2.0
2.0
10.2
-
-
-
2.1
8.2
16.3
17.1
Soleidae
-
-
-
-
-
-
-
-
2.0
-
-
-
-
-
-
-
Solea solea
-
2.1
2.2
13.5
39.6
-
2.0
28.6
55.1
-
-
-
-
-
18.4
56.1
Buglossidium luteum
-
-
2.2
-
4.2
-
-
4.1
49.0
-
-
-
-
2.0
22.4
36.6
Microchirus variegatus
-
-
-
-
-
-
-
-
2.0
-
-
-
-
-
6.1
4.9
Unidentified spp.
-
55.3
84.8
81.1
45.8
36.4
53.1
89.8
32.7
3.7
6.7
58.3
63.8
77.6
65.3
22.0
Total number of stations worked
49
47
46
37
48
11
49
49
49
27
30
48
47
49
49
41
-
4.1
9.8
5.
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